diff options
| -rw-r--r-- | main.go | 57 |
1 files changed, 53 insertions, 4 deletions
@@ -8,11 +8,14 @@ import ( "io" "io/ioutil" "log" + "net" "net/http" "os" "path" "regexp" + "strconv" "strings" + "syscall" "time" "unicode/utf8" ) @@ -245,13 +248,59 @@ func proxy(w http.ResponseWriter, req *http.Request) { } } +// https://www.freedesktop.org/software/systemd/man/sd_listen_fds.html +func socketActivationListener() net.Listener { + pid, err := strconv.Atoi(os.Getenv("LISTEN_PID")) + if err != nil || pid != os.Getpid() { + return nil + } + + nfds, err := strconv.Atoi(os.Getenv("LISTEN_FDS")) + if err != nil || nfds == 0 { + return nil + } else if nfds > 1 { + log.Fatalln("not supporting more than one listening socket") + } + + const firstListenFd = 3 + syscall.CloseOnExec(firstListenFd) + ln, err := net.FileListener(os.NewFile(firstListenFd, "socket activation")) + if err != nil { + log.Fatalln(err) + } + return ln +} + +// Had to copy this from Server.ListenAndServe() +type tcpKeepAliveListener struct{ *net.TCPListener } + +func (ln tcpKeepAliveListener) Accept() (c net.Conn, err error) { + tc, err := ln.AcceptTCP() + if err != nil { + return + } + _ = tc.SetKeepAlive(true) + _ = tc.SetKeepAlivePeriod(3 * time.Minute) + return tc, nil +} + func main() { - // TODO: also try to support systemd socket activation - address := ":8000" + listenAddr := ":8000" if len(os.Args) == 2 { - address = os.Args[1] + listenAddr = os.Args[1] + } + + var listener net.Listener + if ln := socketActivationListener(); listener != nil { + // Keepalives can be set in the systemd unit, see systemd.socket(5) + listener = ln + } else if ln, err := net.Listen("tcp", listenAddr); err != nil { + log.Fatalln(err) + } else { + listener = tcpKeepAliveListener{ln.(*net.TCPListener)} } http.HandleFunc("/", proxy) - log.Fatal(http.ListenAndServe(address, nil)) + // We don't need to clean up properly since we store no data + log.Fatalln(http.Serve(listener, nil)) } |